CN103603267B - Protective device with height-variable sacrificing piles against local scours to bridge pier foundation - Google Patents

Abstract

The invention relates to a protection device for a group of variable-height sacrificial piles against partial scour of bridge pier foundations, which comprises an inflow start pile, an intermediate transition pile and a front end pile arranged in sequence from front to back along the water flow direction in front of the main pier of the bridge. The flow starting pile is a single pile, which is the pile with the lowest height in the protective device. The intermediate transition piles form a group of piles, and every two intermediate transition piles form a group. There is a height difference between the intermediate transition piles of different groups. The end piles in front of the pier are two equal height piles, which are the highest piles in the protective device; the starting pile of the incoming flow breaks up the water flow into two small water flows on the left and right, and then the middle transition pile disturbs the water flow, and the last end pile in front of the pier Diffusion of the flow action ultimately beyond the range affecting the soil around the main piers of the bridge. Compared with the prior art, the device of the present invention can be pre-processed in the factory or processed on site, the actual production process is simple and convenient, the required repair and maintenance investment is small, and it can be put into long-term use at one time, and the cost performance is high.

Description

A protection device for variable-height sacrificial pile groups against partial scour of pier foundations

technical field

The invention relates to a bridge pier anti-scouring device, in particular to a protection device for variable-height sacrificial pile groups resisting partial scour of bridge pier foundations.

Background technique

Bridge engineering is playing an increasingly important role in the modern social economy. Through the bridge, the two sides of the Taiwan Strait will be communicated and exchanges will be promoted, so as to make the economy develop together. However, problems caused by bridge water damage also follow, especially for bridges located in mountainous areas and river estuaries. Due to the complex hydrogeological conditions, the scour effect is more obvious, and bridge water damage accidents occur from time to time. How to better Solving the local scour problem of bridges becomes a major task. However, the current scouring protection methods at home and abroad still remain in the passive protection field, which will lead to increased maintenance and repair costs and more labor required. When the regular repair tasks cannot be completed, water damage caused by local scouring may occur. lost heavily. In order to make up for the limitations of the traditional passive protection method, a new protection method, sacrificial pile protection, is proposed. The key technology is the layout parameters of the pile group, and there is no relevant report so far.

Contents of the invention

The purpose of the present invention is to overcome the passive protection method in the traditional protection, and provide a protection device with variable height sacrificial pile groups to resist the local erosion of the pier foundation. washout effect.

The purpose of the present invention can be achieved through the following technical solutions:

A protection device for a group of variable height sacrificial piles to resist local scour of a pier foundation, which is arranged in front of the main pier of a bridge to be protected. The intermediate transition pile and the end pile in front of the pier, the starting pile of the incoming flow is a single pile, which is the pile with the lowest height in the protective device, and there are several intermediate transition piles to form a group of piles. The transition piles form a group, and there is a height difference between intermediate transition piles of different groups. The front end piles of the pier are two equal height piles, which are the highest piles in the protective device;

The inflow starting pile decomposes the water flow in the first step, breaks up the water flow into two small water flows on the left and right, and then the intermediate transition pile disturbs the water flow, and can elastically control the protective effect of the intermediate transition pile. The above-mentioned end piles in front of the pier are the last link to disturb the incoming flow, and finally spread the action of the water flow beyond the range affecting the soil layer around the main pier of the bridge.

Every two intermediate transition piles form a group, and the height and pile diameter of the two intermediate transition piles in the same group are the same, and they are arranged symmetrically with respect to the connection line between the starting pile of the incoming flow and the main pier of the bridge.

When the intermediate transition piles form two or more groups, the height of the intermediate transition piles of different groups increases gradually along the water flow direction, and the height difference of different groups is determined according to the incoming flow and the condition of the main pier of the bridge, and the intermediate transition piles of different groups The vertical distance between the starting pile of the incoming flow and the main pier of the bridge is getting larger and larger.

There are two front-end piles before the pier, and the two front-end piles are symmetrically arranged relative to the connection line between the starting pile of the incoming flow and the main pier of the bridge.

All the intermediate transition piles and the end piles in front of the pier on the side of the connection line between the starting pile of the incoming flow and the main pier of the bridge form a straight line with the starting pile of the incoming flow, and the straight line forms an incoming flow angle with the direction of the water flow, and the incoming flow angle The size affects the protective effect of the protective device. The flow angle between 25° and 45° should be selected according to the actual situation. When the incoming flow velocity is too high and the direction is single, the angle should be smaller, and when the incoming flow is oblique and the inclination is too large, a larger incoming flow angle should be selected. For engineering convenience, it is advisable to take values in increments of 5°.

The distance between the starting pile of incoming flow and the main pier of the bridge is the maximum pier distance S _max , and the distance between the intermediate transition piles is the pile group spacing S _p . The maximum distance between pier piles should be selected according to the actual situation and the number of piles. S _max is between 2D and 4D, and the pile group spacing S _p is between 0.67D and 1.5D, where D is the diameter of the main pier of the bridge. When the incoming flow velocity is too high and the direction is single, the smaller combination of S _max and S _p should be selected. When the incoming flow is oblique and the inclination is too large, the larger combination of the two should be selected. For engineering convenience, S _max should be taken in increments of 0.5D, and S _p should be uniformly arranged.

The number of the intermediate transition piles and the ending piles in front of the pier affects the protection effect of the protection device. When the number of the intermediate transition piles increases, the protective effect of the protective device increases accordingly. The flow start pile (one) and the front end pile (two) of the pier must exist and the number is fixed. When the number of transition piles in the middle increases, the anti-scour effect will be enhanced. It is advisable to select a total of 5 to 9 piles according to the actual situation, and select the number of piles in increments of 2. When the project has high requirements for anti-scouring, large capital investment, and excessive flow velocity, it is advisable to take a larger number of pile groups.

Different numbers of intermediate transition piles are configured according to different forms of bridge main piers, and different flow angles and maximum distances between piles and piers are selected according to different numbers of intermediate transition piles, so as to maximize the anti-scouring effect.

Compared with the prior art, the device of the present invention can be pre-processed in the factory or processed on-site. Although the theory is complicated, the actual production process is simple and convenient, and the required repair and maintenance investment is small. Once put into long-term use, the cost performance is high.

Description of drawings

Fig. 1 is the front view structure schematic diagram of the device of the present invention in embodiment 1;

Fig. 2 is the side view structural representation of the device of the present invention in embodiment 1;

FIG. 3 is a schematic top view of the device of the present invention in Example 1.

In the figure, 1 is the protective device, 2 is the main pier of the bridge, 3 is the starting pile of the incoming flow, 4 is the intermediate transition pile, 5 is the ending pile before the pier, a is the incoming flow angle, b is the maximum distance between the pier piles, and h is height value.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

A protection device for sacrificial pile groups with variable heights to resist local erosion of bridge pier foundations, as shown in Figures 1 to 3, is arranged in front of the main pier 2 of the bridge to be protected, and is surrounded by a river bed or sea level environment. The protection device 1 includes The direction of water flow is set in sequence from front to back at the inflow starting pile 3, the intermediate transition pile 4 and the front end pile 5 in front of the main pier 2 of the bridge. The inflow starting pile 3 is a single pile, which is the lowest height among the protective devices. The intermediate transition piles 4 are provided with an even number of piles to form a group of piles. Every two intermediate transition piles 4 form a group. The height and pile diameter of the two intermediate transition piles 4 in the same group are the same, and relative to the incoming flow The connecting line between the initial pile 3 and the main pier 2 of the bridge is arranged symmetrically. When the intermediate transition piles 4 form two or more groups, the height of the intermediate transition piles 4 of different groups increases gradually along the water flow direction, and the height difference h of different groups is determined according to the incoming flow and the condition of the main pier 2 of the bridge, and different groups The vertical distance between the intermediate transition pile 4 and the connection line between the incoming flow starting pile 3 and the bridge main pier 2 is getting bigger and bigger. The front end piles 5 of the pier are two equal height piles, which are the highest piles in the protective device. The front end piles 5 of the two piers are symmetrically arranged with respect to the connection line between the incoming flow starting pile 3 and the main pier 2 of the bridge.

All the intermediate transition piles 4 and the front end piles 5 on the side of the line connecting the starting pile 3 of the incoming flow and the main pier 2 of the bridge form a straight line with the starting pile 3 of the incoming flow, and the straight line forms an incoming flow with the direction of the water flow. Angle a, the size of the incoming flow angle a affects the protective effect of the protective device. The flow angle a between 25° and 45° should be selected according to the actual situation. When the incoming flow velocity is too high and the direction is single, the angle should be smaller, and when the incoming flow is oblique and the inclination is too large, a larger incoming flow angle should be selected. For engineering convenience, it is advisable to take values in increments of 5°. The distance between the starting pile 3 of the incoming flow and the main pier 2 of the bridge is the maximum pier distance S _max , which is represented by b in the figure, and the distance between the intermediate transition piles 4 is the pile group spacing S _p , and the pier should be selected according to the actual situation and the number of pile groups The maximum pile distance S _max is between 2D and 4D, and the pile group spacing S _p is between 0.67D and 1.5D, where D is the diameter of the main pier of the bridge. When the incoming flow velocity is too high and the direction is single, the smaller combination of S _max and S _p should be selected. When the incoming flow is oblique and the inclination is too large, the larger combination of the two should be selected. For engineering convenience, S _max should be taken in increments of 0.5D, and S _p should be uniformly arranged.

How much the quantity of the intermediate transition pile 4 affects the protective effect of the protective device. Different numbers of intermediate transition piles 4 are configured according to different forms of bridge main piers 2, and different flow angles a and maximum distances between pile piers are selected according to different numbers of intermediate transition piles 4, so as to maximize the anti-scouring effect.

The starting pile 3 of the incoming flow is the first step to disturb the incoming flow, and it is also a relatively critical step. The first step is to decompose the water flow, break the water flow into two small water flows on the left and right, and then the intermediate transition pile 4 will disturb the water flow. The protection effect of the transition pile 4 in the middle can be elastically controlled, and the finishing pile 5 in front of the pier is the last link to the disturbance of the incoming flow, and the effect of the water flow is finally diffused beyond the range affecting the soil layer around the main pier 2 of the bridge to achieve the protection effect.

In this embodiment, when the bridge main pier D=4.5m, the height of the bridge main pier exposed to the water surface H=20m, the water flow velocity is relatively large, the degree of inclination is medium, and when the project protection investment is low, the sacrificial piles (including the flow starting piles) , transition pile in the middle and end pile in front of the pier), the pile diameter is d=1m, the exposed height of the sacrificial pile is h _max =18m, the increment of the height of the sacrificial pile is h=0.2h _max =3.6m, and the flow angle of the arrangement is α = 30°, the maximum distance between pier piles b = S _max = 10m, S _p = 0.67D = 3m, the number of piles is 5, and the arrangement is shown in Figures 1, 2 and 3.

Claims (6)

1. an And of Varying Depth sacrifices the protector that pile group resists pier footing local scour, be arranged on Main Pier of Bridges front to be protected, it is characterized in that, this protector comprises the initial stake of incoming flow being successively set on Main Pier of Bridges front along water (flow) direction from front to back, middle transition stake and the stake of pier front ending, the initial stake of described incoming flow is a single pile, it is stake highly minimum in protector, described middle transition stake is provided with several, form a clump of piles, every two middle transition stakes form a group, difference in height is there is between the middle transition stake of different group, before described pier, ending stake is two equal altitudes stakes, it is stake highly the highest in protector,

Current are carried out first step decomposition by the initial stake of described incoming flow, current are broken up into two strands, left and right weep, current are dredged upset by middle transition stake described afterwards, before last described pier ending stake flow action is finally diffused into affect soil layer around Main Pier of Bridges scope outside.

2. a kind of And of Varying Depth according to claim 1 sacrifices the protector of pile group opposing pier footing local scour, it is characterized in that, every two middle transition stakes form a group, two middle transition stakes height in same group and stake footpath identical, and to be symmetrical set relative to the line of the initial stake of incoming flow and Main Pier of Bridges.

3. a kind of And of Varying Depth according to claim 1 sacrifices the protector of pile group opposing pier footing local scour, it is characterized in that, when middle transition stake forms two or more group, the middle transition stake of different group is cumulative along water (flow) direction height, and the middle transition stake of different group is increasing to the vertical distance of the line of the initial stake of incoming flow and Main Pier of Bridges.

4. a kind of And of Varying Depth according to claim 1 sacrifices the protector of pile group opposing pier footing local scour, it is characterized in that, before described pier, ending stake is two, and before two piers, ending stake is symmetrical set relative to the line of the initial stake of incoming flow and Main Pier of Bridges.

5. a kind of And of Varying Depth according to claim 1 sacrifices the protector of pile group opposing pier footing local scour, it is characterized in that, finish up before being positioned at all middle transition stakes of the line side of the initial stake of incoming flow and Main Pier of Bridges and pier stake and the initial stake of incoming flow forms straight line, and this straight line and water (flow) direction form incoming flow angle, incoming flow angle selects 25 ° to 45 °.

6. a kind of And of Varying Depth according to claim 1 sacrifices the protector of pile group opposing pier footing local scour, it is characterized in that, the distance of the initial stake of described incoming flow and Main Pier of Bridges is that pier stake is maximum apart from S _max, the spacing of described middle transition stake is clump of piles interval S _p, pier stake is maximum apart from S _maxbetween 2D to 4D, clump of piles interval S _pbetween 0.67D to 1.5D, wherein, D is the diameter of Main Pier of Bridges.